What is Jig and Fixture - Types & their differences

Hello friends ,Today I am talking about Jig and Fixture,Which is widely used in mass production for holding the job and also for guiding the tool.

In this topic firstly we will know about what is jig and fixture and then know various types of jig and fixture and their materials, fundamental principle,etc.

After completing this topic then we will know that what is difference between jig and fixture.

So let's start,

Definition of Jig and Fixture

Jig

A jig is a device that captures and locates the work, and guides and controls one or more cutting tools. 
The task is to hold and guide the tool in such a way that they are positioned in the correct position with respect to each other.

jig and fixture

Fixture

A fixture is a type of device used to hold and locate a workpiece at the time of inspection or for a manufacturing operation. 
The fixtures do not guide the tool.


difference between jig and fixture


Advantages of Using Jig and Fixture

There are so many advantages which as follows

• Markings and settings are not required

• Uniform parts can be made.

• The production volume increases due to rapid clamping and releasing.

• Reduced operator fatigue.

Fundamental Principles of Jig and Fixture

The following pointers should be kept in mind when designing jig and fixture

• Location loading and unloading

• Clamping

• Motion saving

• Removing machined parts

• Strength and beauty

• Guidance of the tool.

• Security

Types of Jig

The jig is a device used in mass production to hold the job in position and guide the tool. 
It is mostly used for drilling/boring. The jig is often used with bushings made of tool steel to guide the tool.

According to the work they are found in different types which are as follows

1. Template Jig

2. Plate Jig

3. Angle Plate Jig

4. Channel Jig

5. Leaf Jig

6. Indexing Jig

1. Template Jig

This is the simplest type of jig that can be produced at a very low cost.
Can be with or without sleeves or bushings. 
If no bushings are used, the entire jig plate is hardened.
In use, this clamp is fixed over work or without clamp in work.

2. Plate Jig

This jig is similar to a template jig, but is found in the plate jig belt in clamp to hold the job. It can also be with or without bushings.

3. Angle Plate Jig

This jig is often used for jobs that are machined in right angles with its mounting locator.
If the angle of machining is beyond 90° a modified angle plate jig is used.


4. Channel Jig

This is a box type jig whose size is very simple.
The job is held between the two sides, and the operation is performed from the third side.

5. Leaf Jig

This jig is found as a small size box jig with low or latched hinged limbs, which allows easy loading and unloading of jobs.

6. Indexing Jig

This jig is mostly used to make holes in precision spaces or to perform other machining operations around the job.
Large size indexing jigs are called rotary jigs.

Types of Fixture

Fixture is a device which is used to hold the job's only.

According to work, they are found in different types.

1. Plate Fixture

2. Angle Plate Fixture

3. Indexing Fixture

4. Vice - Jaw Fixture

1. Plate Fixture

It is a simple type of fixer that is usually made of flat plate.
Various clamps and locators are used with this fixture to hold and locate the job.

2. Angle Plate Fixture

This fixture is mostly used to hold a job that is machined in right angles with its locator. Modified angle plate fixtures are used when machining is required at any angle other than 90 °

3. Indexing Fixture

This fixture is similar to the indexing jig used for machining the job in equal spaces.

4.Vice - Jaw Fixture

These fixtures are mostly used for machining small jobs. They are shaped according to the job and are replaced by standard jaw plates of vice.

Supporting and Locating in Jig and Fixture

The following signals should be kept in mind while locating and supporting jigs and fixtures.

1. Referencing 

If the job is brought to the correct position with respect to the tool to perform machining operations in precision, it is called referencing.

2. Position of Locators

While positioning locators, the machined surface of the job machine should always be in contact with the locator as far as possible. If the locator is prone to any blockage due to chips, etc., then the locators should be relieved.

Materials for Jig and Fixture

Materials used for jigs and fixtures are divided into the following three classes -

1. Ferrous Materials

2. Non-ferrous Materials

3. Non-metallic Materials

Ferrous Materials

Ferrous materials are often used to make jigs and fixtures.

Usually, the following ferrous materials are used

(A) Cast Iron

(B) Carbon steel
 
(C) Alloy Steel

(D) Tool Steel

(A) Cast Iron

It is used to make jigs and fixtures because it is cheaper and takes less time to fabricate.

(B) Carbon steel

The following carbon steel is often used to make jig and fixture 

(i) Low carbon steel

(ii) Medium Carbon Steel

(iii) High Carbon Steel

(i) Low carbon steel

It is mostly used to make base plates or supports of jigs and fixtures.

(ii) Medium Carbon Steel

It is often used for jigs and fixtures to make clamps, studs, nuts that require less toughness.

(iii) High Carbon Steel

It is often used to make bushings, and locators, wear pads, etc.For jigs and fixtures.

(C ) Alloy Steel

It is not used mostly for making jigs and fixtures, but it can be used for certain tasks.

(D) Tool Steel

This steel can be made in the right standard. It is used in jigs and fixtures to form parts that require high wear resistance. Often jig bushings are made from this steel.

2. Non - Ferrous Materials

Non-ferrous materials are often used to make jigs and fixtures these are following

(A) Aluminium

(B) Magnesium

(C) Bismuth

(A) Aluminium

It is mostly used for jig or fixture.
Because it is light in weight and has good machinability. It does not require heat treatment process to increase its hardness.

(B) Magnesium

It is also used to make jigs or fixers because it is lighter in weight and can be machined easily than aluminium and steel.

(C) Bismuth

It is a low melting alloy used to make special holding devices for jigs and fixtures such as Nest or Vice Joss.

3. Non - Metallic Materials

Non-metallic materials are also used to make jigs and fixtures.
Jigs or fixtures used for limited production can be made with these materials better, cheaper and quicker.

Often the following  Non-metallic materials are used

(A) Urethane

(B) Wood

(C) Epoxy and Plastic Resin

(A) Urethane

It is often used for secondary clamping. A block made of urethane is placed between the job and the clamp. While clamping, it captures the party well and does not allow the job surface to deteriorate.

(B) Wood

It is used for jigs and fixtures that do not require precision. It is used to make special bushings and inserts. The bushings made of this material have external grooves so that when the bushings are pressed or pasted into the jig or fixtures, the grip is very good.

(C) Epoxy and Plastic Resin

It is mostly used for making special clamps for jigs or fixtures.  Nest and jaws are often made from this material, which are toughed and cheap. Resins are light in weight, strong, toughed and often deformable.

Difference between Jig and Fixture

There are most common difference between Jigs and Fixtures which are as follows

 Jig

1. Hold and locates the work and guides the tool.

 2. They are made in light loads for quick handling, and it is often not necessary to clamp them on the table.

 3. Jigs are used to hold the work and guide the tool while drilling, reaming or tapping operations.

 Fixture

1. Hold the work and hold it in position, but does not guide the tool.

2. Often heavy in texture and bolted firmly to the machine table with bolts.

3. Fixtures are often used to hold work for milling, grinding, planning, shaping and turning operations.

So, friends here I discussed about  Jig and Fixture and its types I hope you like these topic if any query then you can ask me through comment.

Thank You

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